| 夏季金塔绿洲风环流的数值模拟及结构分析 |
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| 引用本文： | 文莉娟,吕世华,张宇,李锁锁.夏季金塔绿洲风环流的数值模拟及结构分析[J].高原气象,2005,24(4):478-486. |
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| 作者姓名： | 文莉娟 吕世华 张宇 李锁锁 |
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| 作者单位： | 中国科学院,寒区旱区环境与工程研究所,甘肃省干旱气候变化与减灾重点实验室,甘肃,兰州,730000 |
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| 基金项目： | 国家自然科学基金重点项目（40233035）;中国科学院方向性创新项目（KZCX3-SW-329共同资助 |
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| 摘 要： | 利用中尺度数值模式MM5，替换了模式第三重嵌套模拟域中金塔绿洲及周围地区与实际不符的植被类型，对2004年7月5日金塔绿洲效应进行了较为成功的模拟。模拟结果显示：白天绿洲是一冷源，这一现象可维持到3000m左右，临近地面沙漠绿洲温差最大，冷中心强度由低层向高层逐渐减弱；气压距平场低层为沙漠低，绿洲高，较高层则反之，转变发生在1300m。低层绿洲风盛行，随高度增加，辐散风渐弱；750hPa以上转为以背景风为主，存在向绿洲中心辐合的趋势；距平风场低层为辐散风，高层为辐合风，绿洲中部风速较小，越远离风场辐散（辐合）中心，风速越大；沙漠上为上升气流，绿洲基本上全为下沉运动所控制，但剖面图上显示绿洲上并不是只有一个闭合中心，且绿洲上、下沉运动的顶部高度也不一致，绿洲中心最低，两侧逐渐增高。最大下沉运动出现在绿洲边缘；绿洲低层分布着强度均匀的辐散区，而沙漠上则为零散辐合区，750hPa辐合区开始侵入绿洲，700hPa时绿洲基本为辐合区，绿洲边缘辐合最强，沙漠以辐散为主，分布少许辐合中心。比湿同湿位温具有相似特征，在一定高度以上，在下沉气流的作用和西风背景场的影响下等值线形成低槽形状，低槽中心从高层向低层、由西向东偏移。
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| 关 键 词： | 绿洲风 三维结构 数值模拟 MM5模式 |
| 文章编号： | 1000-0534（2005）04-0478-10 |
| 收稿时间： | 2004-12-16 |
| 修稿时间： | 2004-12-16 |
Numerical Simulation and Structure Analyses of the Local Circulation in Jinta Oasis Summer |
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| WEN Li-juan,U Shi-hua,ZHANG Yu,LI Suo-suo.Numerical Simulation and Structure Analyses of the Local Circulation in Jinta Oasis Summer[J].Plateau Meteorology,2005,24(4):478-486. |
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| Authors: | WEN Li-juan U Shi-hua ZHANG Yu LI Suo-suo |
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| Abstract: | The characteristics of Jinta Oasis on 5 July, 2004 was successfully simulated using the mesoscale model MM5 on the basis of replacing the landuse in the domain 3. The simulated results showed that in the day time, the oasis was a cold source, it maintains till 3000 m above the ground and the temperature-difference between the oasis and desert was the highest near the ground and the intensity of cold center weakened from low level to high level; the departure of the pressure field was positive on lower levels and negative on higher levels on the oasis, and the transition of them happened near 1300 m heights, and vice versa in desert; on lower levels the wind blew from the oasis, and the divergence weakened with the height. Above 750 hPa, the background wind dominated and there were some convergent; the anomaly wind field are divergent on lower levels and convergent on higher levels. The wind velocity was the smallest near the divergent/convergent center on the oasis and increased far from it. There was updraft on deserts and downdraft dominated the whole oasis. There were more than one downdraft center, and the height of it was not the same, which was the lowest on the center of oasis and higher on both sides of oasis. The strongest downdraft appeared on the edge of the oasis; Divergence distributed uniformly over lower levels of oasis and scattered convergence distributed on desert, 750 hPa convergence region began to appear over the oasis. On 700 hPa it dominated over the oasis, and convergence was the strongest on the edge of the oasis and desert. While over desert, there were almost the divergent and a little of convergent. Specific humidity and moist potential temperature have similar characteristics. Up a certain height and above it, their contours formed low trough and the centers of trough moved from high to low and from west to east under the influence of the downdraft and the background of west wind. |
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| Keywords: | Oasis wind 3D-structure Numerical simulation MM5 |
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